The quest for an efficient recording scheme for disk files continues to be one of the highest priorities. Increasing data storage density and the need for apparatus having extended lives drive this search.
Disk files are information storage devices which utilize at least one rotatable data storage disk with concentric data tracks containing data information, a transducer for reading the data from or writing the data to the various tracks, a slider for holding the transducer adjacent to the track generally in a flying mode above the media, a suspension for resiliently holding the slider and the transducer over the tracks, and a positioning actuator connected to the combination for moving the transducer to the desired track and maintaining the transducer over the track center line during a read or a write operation. The transducer is attached to the air bearing slider which supports both above the track of the disk by a cushion of air that is generated by the rotating disk or in contact with the disk. A suspension provides a high spring stiffness and dimensional stability between the slider and the actuator arm. The suspension is required to maintain the transducer and the slider adjacent to the data surface of the disk with as low a loading force as possible. The actuator positions the transducer over the correct track according to the data desired on a read operation or to the correct track for placement of the data during a write operation. The actuator is controlled to position the transducer over the correct track by shifting the combination suspension-transducer-slider assembly generally transverse to the motion of the track.
In conventional disk drives, the transducer and the slider are formed separately from the suspension and then attached through an operator controlled precision operation. The parts are small and the positioning of each relative to the other must be exact. The transducer must be exactly positioned relative to the track which in turn means that the suspension must be exactly positioned onto the slider. The suspension must provide flexibility and pitch and roll motion for the slider relative to the direction of motion of the rotating disk and yet provide resistance to yaw motion. Any error in the placement of the suspension relative to the slider results in the destruction of both pieces. The conductor leads are directed along the suspension and connected to an amplifier placed on the suspension or on the actuator. The conductor leads must not add to the spring stiffness of the slider while providing good electrical interconnection. The conductor leads are generally bonded by soldering, for instance, to both the transducer output leads and the amplifier by an operator. Again, errors can cause destruction of the entire combination.
The U.S. Pat. No. 4,670,804 to Kant et al. assigned to the assignee of the present invention, describes a slider-suspension assembly that includes flexible sheets of material for the suspension to which the conductors for the transducer are deposited and which support the slider and the transducer combination. The stainless steel suspension of the prior art is replaced by the flexible sheet onto which the conductors are deposited. In this patent, the polyimide flexible sheets are formed separately from the slider/transducer combination and then attached to each other by gluing, for instance. There is no showing of a combination transducer/slider/suspension assembly that requires no further connection step between the suspension and the slider.
It is known that the suspension arm can be formed from a polyimide material with the conductors to the transducer deposited directly on the polyimide suspension. U.S. Pat. No. 4,789,914 to Ainslie et al. and assigned to the assignee of the present invention, discloses that contact soldering can be used to connect the suspension containing the conductors directly to a slider. The transducer is already deposited on the slider. The slider includes conductor pads and interconnecting leads deposited on the slider between the conductor pads and the transducer. Again the slider and transducer are separately produced from the suspension arm and then interconnected later through contact soldering as disclosed in this patent. As with the remainder of the known prior art, the slider and transducer portion of the combination is produced separately from the suspension assembly which includes interconnecting conductors. There is no showing of a combination transducer/slider/suspension with conductors nor a method for making the combination.
Contact reading techniques have shown some great promise in recent years. Slider apparatus with a suspension made of an active material achieves contact recording by cycling the transducer down only when a read/write operation is desired. The remainder of the time the slider flies at a height above disk contact. Another approach to contact recording is a scheme in which a "flexible" head is rubbed against the disk surface. The head used in this approach is fabricated by building up a thin film of material on a substrate and then releasing the thin film. For example, U.S. Pat. No. 5,041,932 to Hamilton, assigned to Censtor Corp., discloses a low mass, integrated transducer/flexure/conductor structure for use in contact recording and reading of information. However, the "flexible" head approach requires an elaborate mounting mechanism for proper and precise control.
It has been found that a vertical transducer head achieves several advantages; the most pronounced advantage is the fabrication of the head windings along the length of the wafer. This construction accommodates a large change in the pole tip length caused by mechanical wear over the life of the file and thereby increases the life of the overall apparatus.
Unfortunately, all of these schemes have associated with them several disadvantages which limit their use and application. It is estimated that there are 400 micro inches of head wear over a typical product life. This large amount of wear restricts the applicability of many of these approaches. The pole tips in a conventional head are usually only about one micron long and wear away rapidly in this application
Additionally, while the thin film fabrication allows the integration of the head onto the suspension, this arrangement requires a large amount of wafer area which reduces the head yields per wafer to a level much below conventional head production processes and below an acceptable level.
It therefore is an object of the present invention to provide a disk system and especially a transducer and suspension system that overcomes the adversities of the prior art.
It is another object of the present invention to provide an enhanced suspension and transducer element.
Another object of the present invention is to provide a low mass suspension-transducer with decreased head wear characteristics.
Yet another object is to provide a suspension-transducer assembly which is useful for contact recording.
Still another object of the present invention is to produce a thin film suspension-transducer which can be controllably activated.
Another object is to provide a recording drive that uses a thin film suspension-transducer of the present invention.